1. Field of the Invention
The invention relates to accumulating live roller conveyors in which articles proceeding in single file are stopped when a lead article is obstructed. The invention particularly pertains to conveyors of this type in which the accumulating articles either do not touch each other or touch each other with minimal pressure and the conveyor exerts no effective propelling force on most of the accumulated articles. This may be referred to as "a zero pressure accumulating conveyor." The invention also pertains to accumulating conveyors which have belt driven powered rollers. Moreover, the invention is of the type in which the power to operate the accumulation process is taken from the moving belt itself without any additional outside power source. The accumulating components are thus "mechanically operated" rather than power operated by an outside source such as compressed air.
2. Description of the Prior Art
Typical of the patents which disclose belt driven live roller accumulating conveyors in Poel et al U.S. Pat. No. 3,012,652 in which the driving belt is beneath the article-supporting rollers. Another belt driven powered roll conveyor is shown in Olk et al U.S. Pat. No. 2,827,153. These patents show various means for adjusting the pressure rollers for the belt. In Pipp U.S. Pat. No. 3,612,247, the article-supporting rollers are yieldingly biased upwardly out of contact with the driving belt and are pressed thereagainst by the articles, sensing devices causing expansible chambers to hold the rollers out of engagement with the belt when movement of the lead article is interrupted. A patent showing eccentric rollers for accumulating articles but without sensors or accumulating zones, is Forsyth et al U.S. Pat. No. 3,266,617. De Good et al U.S. Pat. No. 3,253,697 shows eccentric pressure rollers beneath a belt in accumulating zones which are stopped by sensors, the system operating on a different principle than that of the present invention.